Strong Coupling of Light with Extremely Thin Non-Close-Packing Colloidal Crystals: Experimental and Theoretical Studies

Single and double layers of non-close-packing silica colloidal crystals are prepared using the self-assembly and chemical etching methods. A modulation of size reduction of 21% of silica particles is reported while sustaining the ordering of the structures. As a result of the coupling between light and the two-dimensional (2D) photonic structures, several dips are clearly observed in the measured optical transmission spectra. With decreasing the dielectric particle size, the transmission dips undergo blue shifts and simultaneously become deep. The measured transmission spectra are in good agreement with the theoretical calculations by taking the energy dissipation of the semi-infinite dielectric substrate for the 2D photonic crystals.